Stanchions are provided in practice for supporting horizontal supports of tarpaulin structures, such as, for example, sliding tarpaulins. A tarpaulin structure of this type can be designed for bodies of truck platforms or of semitrailers, but also for containers or railroad freight cars. In the case of sliding tarpaulins, in order to be able to rapidly load or unload them, the side tarpaulins hanging down from the supports can be pushed together, and also the roof tarpaulin, which runs between the longitudinal supports, can be pushed together by means of movable bows, on which the roof tarpaulin is secured. In order to further improve the access to the loading space, the tarpaulin frames of the sliding tarpaulins are designed such that they can easily be removed. The intention is, in particular, for the central stanchions to be able to be rapidly removed, but frequently also the corner stanchions, which are also referred to as posts, the supports also having to be removed in this second case while said supports, if only the central stanchions are released, are adequately supported by the posts if the sliding tarpaulin is not moved. Other tarpaulin structures support a chassis roof which is formed, for example, with little weight from a plastic sheeting riveted on the longitudinal supports, so that the displacement only of the side tarpaulins is envisaged.
In practice, a series of stanchion arrangements is known where one stanchion in each case can be locked on a corresponding fixing member, which is also referred to as a stanchion shoe, by means of a rapidly releasable fastening, the stanchion shoe as a rule being secured, for example by screwing or by welding, on a supporting outer part of the loading area of the sliding tarpaulin, for example on a metal frame which supports wooden battens.
A first embodiment, which is known in practice, of a lockable central stanchion has a lever arrangement with an intermediate lever and a main lever, the intermediate lever being coupled to the stanchion by a first joint and being coupled to the main lever via a second joint, and the main lever having an actuating handle on the long lever arm and a design in the form of a pressing member on the short lever arm. In order to lock the stanchion, the pressing member is fitted behind an upwardly protruding lug of the stanchion shoe and, by actuation of the main lever, the stanchion is pushed away upward by the stanchion shoe via the two levers until the lever arrangement is locked. In this embodiment, the entire load of the stanchion and of the longitudinal support and all of the forces also acting on the stanchion during the journey are transmitted to the stanchion shoe via the two joints, as a result of which the joints are subjected to an extreme amount of stress and the stanchion only has a limited service life. In addition, this embodiment does not have any means of fixing the stanchion in the direction of the longitudinal supports.
A second embodiment, which is known in practice, of a lockable central stanchion has a first lever which is in the manner of an upward clip and is inserted into a U-profile of a stanchion bearing, and a second lever which is coupled to the body of the stanchion and which is coupled via an intermediate lever to a locking wedge which can be shifted axially in the body of the stanchion, the stanchion bearing having a pocket for receiving the locking wedge. First of all, the stanchion, which is at an angle to the first lever, is pivoted in the direction of the stanchion bearing and in the process raised, the vertical forces being conducted via the first lever and its coupling means into the stanchion. Then, by actuation of the second lever, the locking wedge is lowered into the pocket of the stanchion bearing and the stanchion tilting unstably about the joint with the first lever is thereby locked. Only if the first lever and its dynamically greatly stressed joint on the stanchion fail can the locking wedge conduct vertical loads on the stanchion into the intercepting pocket, but this takes place only via the second lever and its coupling means, which is not designed for this purpose. Furthermore, the shiftable locking wedge itself constitutes a further part which is susceptible to wear. The known stanchion arrangement is, however, difficult to handle, since it has to be shifted manually into the raised position.
A third embodiment, which is known in practice, of a lockable central stanchion has a lever which is coupled to the body of the stanchion and one lever arm of which has a handle and the other lever arm of which can be introduced into a U-shaped stanchion bearing, the stanchion being raised by pressing the lever with the handle on to the body of the stanchion. Here too, the vertical forces from the stanchion bearing are conducted into the stanchion via the lever.
It is object of the invention to provide a stanchion for a tarpaulin structure, which can be reliably locked and has an improved service life.